| 年度 | 实际值 |
|---|---|
| 1993 | 26.7 |
| 1994 | |
| 1995 | 22.8 |
| 1996 | 23.2 |
| 1997 | 22.8 |
| 1998 | 20.6 |
| 1999 | 21.3 |
| 2000 | 25.3 |
| 2001 | 1.82 |
| 2002 | |
| 2003 | 31.12 |
| 2004 | 31.48 |
| 2005 | 38 |
| 2006 | 40.18 |
| 2007 | 33.82 |
| 2008 | 32.58 |
| 2009 | |
| 2010 | 35 |
| 2011 | 38.56 |
| 2012 | 39.55 |
| 2013 | 39.68 |
| 2014 | 40.14 |
| 2015 | 35.38 |
| 2016 | 40.56 |
| 2017 | 41.4 |
| 2018 | 42.5 |